MODELLING AND STRUCTURAL ANALYSIS OF REAR AXLE CASING OF TRACTOR

: Automobiles based on the structural stability of the kinematic components. Present project deals with the rear axle casing of Mahindra tractor 275 for the analysis. structural objectives under stress load conditions for different materials of cased ferro alloys. modelling done in Uni-Graphics Nx 12.0 and the analysis carried in Ansys work bench 2020R1. The axle casing breaks due to the cracks formed during running conditions. Considering the problem and taken in to account, the existing model is fed in to the structural analysis. In this analysis, we predict the maximum stress concentration area. To perform the static analysis to find the deformation and tensile stress of the rear axle casing, by applying the various loads is the main objective of the work.

conditions. Considering the problem and taken in to account, the existing model is fed in to the structural analysis. In this analysis, we predict the maximum stress concentration area.

BACKGROUND OF THE STUDY:
The rear axle casing problem occurs only because of continuously running for a long period and also the place where it is functioning. For example highly dry area like where the atmospheric temperature will be more than 39 to 51oC. The company people have a detailed report of it says and out of every 1,000 components 5 components get failed during long running. In this one third of the defective casings is found in dry place area.

LITERATURE REVIEW Meng Qinghua et al [1]
analyzed for fatigue failure of truck rear axle housing excited by random load distribution from the uneven road profile. During operation of the truck the random load acts on the axle housing in vertical direction causes severe impact on the fatigue life of the components, By using random load distribution data the fatigue life of the truck is analyzed and also design optimization is proposed to increase the fatigue life of the components according to the simulation results and location of failure.

G Rajesh Babu et al [2]
carried out the static and dynamic analysis of banjo type rear axle housing by using FE method for two different materials like cast iron and mild steel. The induced deformation in cast iron housing is greater than mild steel housing and also the natural frequencies of the cast iron are lower than the mild steel. Also observed that the stress induced in the cast iron is lower than the mild steel and concluded that the cast iron is preferred for production of rear axle housing. M.M. Topaç et al [3] "Fatigue failure prediction of a rear axle housing prototype by using finite element analysis." Premature fatigue failure of a truck rear axle housing prototype was investigated by using finite element analysis.In the analyses, stress concentrated regions were predicted at the banjo transition area. The regions in which the fatigue cracks originated were well-matched with the results of the analyses. Critical regions determined are subjected to a combined steady and cyclic tensile stress.

Manish S Lande et al [4]
"comparative analysis of tractor's trolley axle by using FEA. (by considering change in materials existing shape and size)" Evaluate that the existing rear axle shaft used in tractor trolley shows that the existing axle has greater factor of safety so unwontedly heavy axle is used for trolley in existing condition which increase the weight of axle as well as cost of axle. But the newly designed axle with different cross section and different material show that we can maximally reduces the 33.92% weight as compare to the existing axle. Also reduces the cost of trolley axle as the weight of the axle reduces. Sanjay Aloni [5] carried out the comparative study on tractor trolley axle by using FE method. The fatigue behavior of the existing axle is analyzed and found that failing before the expected life. Further design optimization and fatigue life analysis is carried out to improve the fatigue life and to reduce the weight of axle by using finite element method. Khairul Ak mal Shamsuddin [6] "Stress Distribution Analysis of Rear Axle Housing by using Finite Elements Analysis" A premature failure that occurred due to the higher loading capacity of the heavy vehicle is studied.. In this analysis, in which the stress are distribute, stress concentration from the load given to the axle housing make the axle housing failure. The reason failure occurs is because the axle housing no longer can prevent the load given onto it. From the several load given, the maximum load for the housing can stand was determined by using FE analysis. The result show that the maximum load can be carried by this rear axle housing is 4224.755 kg ≈ 42000 N.

METHODOLOGY
The word tractor originated from the Latin word "trahere", meaning pull. Today, tractors are used for drawing in, towing or pulling objects that are extremely hard to move. The tractor on farms which is used to push agricultural machineries or trailers that plough or harrow fields. Vol12, Issue2, 2021 ISSN NO: 0745-6999 JOURNAL OF RESOURCE MANAGEMENT AND TECHNOLOGY

REAR AXLE CASING:
The rear axle is one of the components of the tractor which is present in the differential. Its main function is to transmit power from differential to wheel. This component is mounted on the back wheels of the tractor, so it is named as Rear Axle. The rear axle casing is the outer cover of the rear axle. Its main function is to protect the rear axle. The rear axle case is connected to 5 cases of transmission and has an inner peripheral surface, ring gear included in planetary reduction mechanism, ring gear being mounted on inner peripheral surface of rear axle case.

RESULTS AND DISCUSSIONS:
As previously stated, the major assumption made for this analysis was that the effect of tyres and hydraulic suspension ram were not considered in the analysis. There are three stages or processes involved in the static and structural analysis of the component. These are namely pre-processing, processing and post processing. In pre-processing the axle model is set up for analysis by converting it into a finite element model by adding and defining some or all of the following finite element model characteristics. The characteristics defined for the model include the geometry of the model, material used in the model and its properties, type of elements, meshing, boundary conditions or constraints and the loads applied. In processing, convergence and outputs are set and these are discussed in more detail in subsection Post processing was the final stage of analysis where the results of the analysis were analysed, factor of safety calculated and plots of different loading cases and deformed axle model were created.

.3 Analysis of Rear Axle Shaft for Circular Section:
The geometry is drafted based on the dimensions of geometric design parameters. The axle is 3dimensionally modeled then meshed properly to divide it into elements and nodes. Finite element model was generated using free meshed 4 nodes quadratic tetrahedral element due to their flexibility in curved and complex shapes, which has three degrees of freedom per node i.e. translation in x, y, z directions were used. Quality checks and mesh optimization for elements were also performed taking into consideration of aspect ratio, distortion, stretch. Geometric models of rear axle shaft were developed in one sections. The worst load case scenario was found to be the dynamic load case of 3g with wheel force of 9810N and axle angle of 6 0 . The Factor of Safety for the component design was calculated to be 2.84 which were lower than the recommended value of 5.5 to 6.5. The Minimum allowable stress and Maximum allowable stress for the Component design would be 484N/mm2 and 572N/mm2 . It was observed that the fatigue cracks originated from welded areas. Results indicate that the axle shaft fractured in reversed bending fatigue as a result of improper welding. Due to heavy load on rear axle specifically in tractor, its life is reduced. So it is important to analyze optimized design to increase its life run. We can optimize rear axle for increasing mechanical strength and easy manufacturability. The objective of this project is increasing working strength and increasing life cycle of rear axle casing of tractor with using different material. From the bar chart it is clear that the stress produced is minimum in carbon fiber and maximum in e-glass. Ductile cast iron and composite material have 7392.1 and 7482.8 Pascal stress respectively. From the bar chart it is clear that the value of the stress produced into the composite material is less than that of stress calculated, thus the composite material is safer than that of the structural steel. So, we can use this composite material for making the rear axle shaft which has more stress handling capacity than the structural steel.